Written By vibykhmer on Tuesday, April 7, 2009 | 6:25 AM

Kaing Guek Eav, or 'Duch' the director of the Khmer Rouge's most infamous prison S-21, told a Cambodia war crimes tribunal he took part in torture sessions and ordered his subordinates to beat prisoners who were to be 'smashed' to death with an iron bar.Duch was renowned for reading every confession brought to him from the interrogation sessions, often correcting them in red pen. However, he said today, he rarely believed them.

"I never believed the confessions I received told the truth. At most, they were about 40 percent true," he told the Extraordinary Chambers of the Courts of Cambodia (ECCC) in the Cambodian capital Phnom Penh.

The 66-year-old former school-master is in the second week of a hearing at the UN-backed tribunal, charged with crimes against humanity, war crimes, torture and homicide.

He has already accepted responsiblity for the atrocities committed at S-21 under his command, and apologised to his victims but he maintains that he was a scapegoat of Pol Pot's genocidal regime which presided over the death of 1.7 million Cambodians during its 1975 - 1979 rule.

The former school-master is answering questions about M-13, a secret security centre in the jungle he ran from 1971-1975 during the Khmer Rouge insurgency against the US-backed military government.

He was posted to S-21 after impressing his superiors with his fanatical devotion to the communist cause, and his brutally meticulous directorship of M-13.

He told the court M-13 was surrounded by a bamboo fence and shackled prisoners were often held in two-metre deep pits, both to prevent escape and to protect them from US warplanes carpet-bombing the area

He claimed he personally tortured only two people but admitted: "The burden is still on me - it's my responsibility. I would like to apologise to the souls of those who died," he said.

The ECCC is questioning him over M-13 to get a better understanding of the structure of S-21.